Semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of integrated circuit evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling-down also produces a relatively high power dissipation value, which may be addressed by using low power dissipation devices such as complementary metal-oxide-semiconductor (CMOS) devices.
Electrostatic discharge (ESD) is an important concern for ICs. If not handled properly, an ESD event can result in a high voltage that could damage components on the IC. To prevent such ESD damage, many modern day ICs are equipped with an ESD protection device. The ESD protection device is operable to divert electrical current away from other components on the IC during an ESD event, thereby protecting these components from being damaged by the ESD event. Unfortunately, existing ESD protection devices often suffer from drawbacks such as excessive chip area consumption, degraded performance for applications with noisy power, and lack of tunability which may result in circuit design problems.
Therefore, while existing ESD protection devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.